15 July 2015
[h=1]How Aloe vera became a cure-all and cosmetic superstar[/h] Its mucilaginous gel is big business and used daily by many, but until now we had no idea where Aloe vera came from or what makes it so special
Its healing powers are legendary, but we know little about how the gel works (Image: Martin Harvey/Getty)
IF YOU are looking for a celebrity to endorse a beauty product, they don’t come much bigger than Cleopatra. The Egyptian queen’s beauty regime famously included bathing in asses’ milk. But that was probably propaganda put about by her Roman enemies. So what to make of another legend? Cleopatra, the woman who seduced not one but two great Roman leaders, enhanced her charms with a skin-softening gel scooped from inside the succulent leaves of the plant we know as Aloe vera. If true, then she was an early fan of a natural product now worth an estimated $13 billion a year.
Today, the mucilaginous gel has an extraordinary range of uses – as a herbal remedy for ailments ranging from skin diseases and burns to digestive troubles, and as a soothing balm in cosmetics and toiletries, from suntan lotion and antiperspirant to detergent and even toilet paper. Increasingly, powdered gel is added as a health-boosting supplement to foods such as yogurt. It is one of the most widely used natural products in the West.
You might think that there’s little left to learn about such a familiar plant. You couldn’t be more wrong. For a start, nobody knows where it originally came from. Aloe vera has been cultivated in most warm parts of the world for so long that people often believe it has always grown there. But a truly wild population has never been found and the plant is presumed extinct in its ancestral home.
Aloe vera is extinct in the wild, its abundance is thanks to thousands of years of cultivation (Image: Sven Torfinn/Panos)
Even more of a puzzle is why Aloe vera dominates trade so completely when there are more than 500 other species of aloes, many with equally succulent gel-filled leaves. What’s so special about this particular plant? Botanists have turned detective to solve these mysteries.
Historical documents provide some clues. The first reliable record of Aloe vera as a medicine dates from around 65 AD – a century after Cleopatra’s death – when the Greek surgeon Dioscorides wrote De Materia Medica, detailing his accumulated knowledge of medicinal plants. In it, he clearly describes Aloe vera, alongside an accurate illustration. Dioscorides travelled with Emperor Nero’s army and used his favourite healing plant to treat all manner of soldiers’ problems – to soothe sore throats and ulcerated genitals, and get rid of boils and piles. He described, too, how he beat the leaves to a pulp and laid them on wounds to stop bleeding.
By Dioscorides’ day, the “healing plant” was already widely cultivated around the Mediterranean and beyond. You need to dig much further back in time to discover the origins of Aloe vera‘s phenomenal success. “The use of Aloe vera gel probably began centuries or possibly millennia before Dioscorides took it with him on his army campaigns,” says Olwen Grace of London’s Royal Botanic Gardens at Kew. There are ancient references to what might have been Aloe vera, but it is hard to be certain when all you have is a name in an ancient script, a rough painting on the wall of a tomb or a list of ingredients in a prescription on a papyrus. So Grace decided to tackle the problem another way – by delving into the evolutionary history of Aloe vera and its many relatives.
Ancient Greek Dioscorides recorded his use of Aloe vera to treat war wounds as well as piles (Image: Vienna Cod.med.gr.1, fol.15r/ONB)
In a mammoth project to reconstruct the aloe family tree, Grace and her colleague Nina Rønsted, a specialist in the evolution of medicinal plants at the Natural History Museum of Denmark in Copenhagen, teamed up with botanists in Africa and Europe. Together they amassed DNA from nearly 200 aloes from all over their geographical range. By comparing key DNA sequences, the team built a near complete picture of how the hundreds of aloes living today are related, how they evolved and when and where they originated.
The first aloes appeared in southern Africa around 19 million years ago and began to diversify as the subtropical climate started to become more seasonally hot and dry. Struggling to adapt to changing conditions in the far south, they spread north-eastwards until they reached the Horn of Africa. Then, around 5 million years ago, a few dispersed north to the Arabian peninsula, west across central Africa and east to Madagascar, setting the scene for a rapid burst of evolution in a rich variety of new habitats.
Among those that appeared on the Arabian peninsula is a group of seven species that share many features with Aloe vera. Sure enough, a comparison of their DNA showed that these are its closest relatives (BMC Evolutionary Biology, vol 15, p 29). “So we now know that Aloe vera originated somewhere on the Arabian peninsula,” says Grace. “That gives us a starting point in the search for the beginnings of the Aloe vera phenomenon.”
As well as pinpointing the plant’s ancestral home, the pair expected to find an evolutionary explanation for its huge success (see “Mysterious healing powers“). Around 25 per cent of aloe species have some medicinal use, but these are often known only locally, and the few that are traded are small beer in comparison with Aloe vera. So what makes Aloe vera gel special? The answer was a surprise.
[h=2]Accidental hero[/h] A preliminary screening of 30 aloe species indicated that, chemically, there was little to distinguish Aloe vera gel from the others (Phytochemistry, vol 93, p 79). The family tree revealed why. “It’s not a unique lineage so there’s no reason to think Aloe vera has unique chemical properties that might explain its popularity,” says Rønsted. In fact, looking at the family tree, the 120 or so aloes known to have some medicinal use come from many different branches. They don’t share close genetic links but they do share some features: they have large succulent leaves with firm gel, short stems that make leaves easy to harvest and they are easy to grow. People seem to have chosen them for pragmatic reasons, rather than for their chemical properties.
The new evidence suggests Aloe vera‘s commercial success was an accident of human history. In ancient times, the southern Arabian peninsula was a key trading hub (see map). One of the region’s most sought-after products was incense, particularly frankincense and myrrh – resins tapped from local trees. By the 4th century BC, the incense trade was flourishing and there was an established route north across the desert to Egypt and the Mediterranean coast for onward passage to Greece and Rome. Traders had also begun dealing in spices, precious gems and textiles, which were arriving at Arabian ports from Africa, India and beyond. According to the Roman geographer Strabo, traffic on the Incense Road was like an army on the march.
Grace suspects that traders setting out on the long and hazardous journey north took Aloe vera with them. “People in the region had probably been using and cultivating it for generations, and traders would have carried it as a sort of living medicine chest,” she says. It helped that the plant is easy to transport. Cut leaves stay fresh and useful for a long time, and plantlets produced by suckering survive a long time without soil or water – even seemingly dead ones will grow if you plant them. “This is the most likely way it spread to Egypt, Ancient Greece and Rome, then to India and later to the Americas,” says Grace.
Why people chose to use and cultivate Aloe vera rather than one of its close Arabian relatives remains a mystery. “Maybe it had larger leaves, grew closer to town, stayed fresher during transportation or was easier to cultivate,” says Rønsted. “But once people discovered it had healing properties they stuck with it.” Their enthusiasm for this plant could explain why it vanished from the wild. Aloes tend to be restricted to specific habitats, so each species has a limited distribution. “If it only grew in one area and everyone collected them, it could have been wiped out that way,” suggests Rønsted. “Or maybe its habitat now lies under a big city.” Ironically, today Aloe vera is the only aloe that isn’t at risk of extinction, thanks to large-scale cultivation.
And what of Cleopatra’s beauty regime? Alas, contemporary writers failed to mention whether it included Aloe vera gel, so we may never know for sure. But there’s little doubt she could have used it. The plant’s reputation is surely far longer established than the queen’s – it may even predate ancient Egypt.
[h=3]Mysterious healing powers[/h] For at least two millennia, probably far longer, countless people around the world have put their faith in the medicinal properties of Aloe vera.
Early accounts focus mainly on the bitter “juice”, or sap, exuded by cells immediately beneath the leaf’s leathery epidermis. “Bitter aloe” has been used almost continuously since classical times as a powerful purgative, reaching the height of its popularity in the after-dinner pills popped enthusiastically by English diners in the 18th and 19th centuries.
“There is some evidence that the active ingredients are phenolic compounds known as anthraquinones,” says Nina Rønsted at the Natural History Museum of Denmark in Copenhagen. Anthraquinones are what give senna pods and rhubarb their laxative effect.
Unlike the sap, the uses of the gel found inside Aloe vera leaves are many and varied. The modern surge of interest began in the US in the 1930s after doctors found it helped heal skin damaged or burned by overexposure to X-rays, and it became an increasingly popular treatment for cancer, eczema and even hair removal at the time.
Long before this, however, the Chinese applied Aloe vera gel to clear dermatitis. In India, people have dabbed it on sore eyes and inflamed joints for centuries. The Javanese slathered chopped gel on burns and drank it mixed with rosewater as a treatment for TB and gonorrhoea. Malaysians and Mexicans pressed slabs of gel to both aching foreheads and tumours. Jamaicans boiled the leaves with salt to cure constipation and applied cut leaves to treat damaged nerves and tendons. Coughs, colds, bruises, bronchitis and even baldness – there were few complaints that someone somewhere didn’t treat with Aloe vera.
Despite the plant’s widespread use, we lack clinical evidence that the gel has the healing powers claimed for it, says Rønsted. She and her colleagues are addressing this with an investigation into the beneficial effects of polysaccharides found in various species of aloe, comparing their ability to enhance immune defence and repair damaged skin.
“We know too little about the chemistry of these complex sugars,” says Rønsted. “They are very hard to analyse and we may yet find differences in the gel of different species.” The findings might even point to plants with greater powers than Aloe vera.
https://www.newscientist.com/articl...era-became-a-cure-all-and-cosmetic-superstar/
[h=1]How Aloe vera became a cure-all and cosmetic superstar[/h] Its mucilaginous gel is big business and used daily by many, but until now we had no idea where Aloe vera came from or what makes it so special
IF YOU are looking for a celebrity to endorse a beauty product, they don’t come much bigger than Cleopatra. The Egyptian queen’s beauty regime famously included bathing in asses’ milk. But that was probably propaganda put about by her Roman enemies. So what to make of another legend? Cleopatra, the woman who seduced not one but two great Roman leaders, enhanced her charms with a skin-softening gel scooped from inside the succulent leaves of the plant we know as Aloe vera. If true, then she was an early fan of a natural product now worth an estimated $13 billion a year.
Today, the mucilaginous gel has an extraordinary range of uses – as a herbal remedy for ailments ranging from skin diseases and burns to digestive troubles, and as a soothing balm in cosmetics and toiletries, from suntan lotion and antiperspirant to detergent and even toilet paper. Increasingly, powdered gel is added as a health-boosting supplement to foods such as yogurt. It is one of the most widely used natural products in the West.
You might think that there’s little left to learn about such a familiar plant. You couldn’t be more wrong. For a start, nobody knows where it originally came from. Aloe vera has been cultivated in most warm parts of the world for so long that people often believe it has always grown there. But a truly wild population has never been found and the plant is presumed extinct in its ancestral home.
Even more of a puzzle is why Aloe vera dominates trade so completely when there are more than 500 other species of aloes, many with equally succulent gel-filled leaves. What’s so special about this particular plant? Botanists have turned detective to solve these mysteries.
Historical documents provide some clues. The first reliable record of Aloe vera as a medicine dates from around 65 AD – a century after Cleopatra’s death – when the Greek surgeon Dioscorides wrote De Materia Medica, detailing his accumulated knowledge of medicinal plants. In it, he clearly describes Aloe vera, alongside an accurate illustration. Dioscorides travelled with Emperor Nero’s army and used his favourite healing plant to treat all manner of soldiers’ problems – to soothe sore throats and ulcerated genitals, and get rid of boils and piles. He described, too, how he beat the leaves to a pulp and laid them on wounds to stop bleeding.
By Dioscorides’ day, the “healing plant” was already widely cultivated around the Mediterranean and beyond. You need to dig much further back in time to discover the origins of Aloe vera‘s phenomenal success. “The use of Aloe vera gel probably began centuries or possibly millennia before Dioscorides took it with him on his army campaigns,” says Olwen Grace of London’s Royal Botanic Gardens at Kew. There are ancient references to what might have been Aloe vera, but it is hard to be certain when all you have is a name in an ancient script, a rough painting on the wall of a tomb or a list of ingredients in a prescription on a papyrus. So Grace decided to tackle the problem another way – by delving into the evolutionary history of Aloe vera and its many relatives.
In a mammoth project to reconstruct the aloe family tree, Grace and her colleague Nina Rønsted, a specialist in the evolution of medicinal plants at the Natural History Museum of Denmark in Copenhagen, teamed up with botanists in Africa and Europe. Together they amassed DNA from nearly 200 aloes from all over their geographical range. By comparing key DNA sequences, the team built a near complete picture of how the hundreds of aloes living today are related, how they evolved and when and where they originated.
The first aloes appeared in southern Africa around 19 million years ago and began to diversify as the subtropical climate started to become more seasonally hot and dry. Struggling to adapt to changing conditions in the far south, they spread north-eastwards until they reached the Horn of Africa. Then, around 5 million years ago, a few dispersed north to the Arabian peninsula, west across central Africa and east to Madagascar, setting the scene for a rapid burst of evolution in a rich variety of new habitats.
Among those that appeared on the Arabian peninsula is a group of seven species that share many features with Aloe vera. Sure enough, a comparison of their DNA showed that these are its closest relatives (BMC Evolutionary Biology, vol 15, p 29). “So we now know that Aloe vera originated somewhere on the Arabian peninsula,” says Grace. “That gives us a starting point in the search for the beginnings of the Aloe vera phenomenon.”
As well as pinpointing the plant’s ancestral home, the pair expected to find an evolutionary explanation for its huge success (see “Mysterious healing powers“). Around 25 per cent of aloe species have some medicinal use, but these are often known only locally, and the few that are traded are small beer in comparison with Aloe vera. So what makes Aloe vera gel special? The answer was a surprise.
[h=2]Accidental hero[/h] A preliminary screening of 30 aloe species indicated that, chemically, there was little to distinguish Aloe vera gel from the others (Phytochemistry, vol 93, p 79). The family tree revealed why. “It’s not a unique lineage so there’s no reason to think Aloe vera has unique chemical properties that might explain its popularity,” says Rønsted. In fact, looking at the family tree, the 120 or so aloes known to have some medicinal use come from many different branches. They don’t share close genetic links but they do share some features: they have large succulent leaves with firm gel, short stems that make leaves easy to harvest and they are easy to grow. People seem to have chosen them for pragmatic reasons, rather than for their chemical properties.
The new evidence suggests Aloe vera‘s commercial success was an accident of human history. In ancient times, the southern Arabian peninsula was a key trading hub (see map). One of the region’s most sought-after products was incense, particularly frankincense and myrrh – resins tapped from local trees. By the 4th century BC, the incense trade was flourishing and there was an established route north across the desert to Egypt and the Mediterranean coast for onward passage to Greece and Rome. Traders had also begun dealing in spices, precious gems and textiles, which were arriving at Arabian ports from Africa, India and beyond. According to the Roman geographer Strabo, traffic on the Incense Road was like an army on the march.
Grace suspects that traders setting out on the long and hazardous journey north took Aloe vera with them. “People in the region had probably been using and cultivating it for generations, and traders would have carried it as a sort of living medicine chest,” she says. It helped that the plant is easy to transport. Cut leaves stay fresh and useful for a long time, and plantlets produced by suckering survive a long time without soil or water – even seemingly dead ones will grow if you plant them. “This is the most likely way it spread to Egypt, Ancient Greece and Rome, then to India and later to the Americas,” says Grace.Why people chose to use and cultivate Aloe vera rather than one of its close Arabian relatives remains a mystery. “Maybe it had larger leaves, grew closer to town, stayed fresher during transportation or was easier to cultivate,” says Rønsted. “But once people discovered it had healing properties they stuck with it.” Their enthusiasm for this plant could explain why it vanished from the wild. Aloes tend to be restricted to specific habitats, so each species has a limited distribution. “If it only grew in one area and everyone collected them, it could have been wiped out that way,” suggests Rønsted. “Or maybe its habitat now lies under a big city.” Ironically, today Aloe vera is the only aloe that isn’t at risk of extinction, thanks to large-scale cultivation.
And what of Cleopatra’s beauty regime? Alas, contemporary writers failed to mention whether it included Aloe vera gel, so we may never know for sure. But there’s little doubt she could have used it. The plant’s reputation is surely far longer established than the queen’s – it may even predate ancient Egypt.
[h=3]Mysterious healing powers[/h] For at least two millennia, probably far longer, countless people around the world have put their faith in the medicinal properties of Aloe vera.
Early accounts focus mainly on the bitter “juice”, or sap, exuded by cells immediately beneath the leaf’s leathery epidermis. “Bitter aloe” has been used almost continuously since classical times as a powerful purgative, reaching the height of its popularity in the after-dinner pills popped enthusiastically by English diners in the 18th and 19th centuries.
“There is some evidence that the active ingredients are phenolic compounds known as anthraquinones,” says Nina Rønsted at the Natural History Museum of Denmark in Copenhagen. Anthraquinones are what give senna pods and rhubarb their laxative effect.
Unlike the sap, the uses of the gel found inside Aloe vera leaves are many and varied. The modern surge of interest began in the US in the 1930s after doctors found it helped heal skin damaged or burned by overexposure to X-rays, and it became an increasingly popular treatment for cancer, eczema and even hair removal at the time.
Long before this, however, the Chinese applied Aloe vera gel to clear dermatitis. In India, people have dabbed it on sore eyes and inflamed joints for centuries. The Javanese slathered chopped gel on burns and drank it mixed with rosewater as a treatment for TB and gonorrhoea. Malaysians and Mexicans pressed slabs of gel to both aching foreheads and tumours. Jamaicans boiled the leaves with salt to cure constipation and applied cut leaves to treat damaged nerves and tendons. Coughs, colds, bruises, bronchitis and even baldness – there were few complaints that someone somewhere didn’t treat with Aloe vera.
Despite the plant’s widespread use, we lack clinical evidence that the gel has the healing powers claimed for it, says Rønsted. She and her colleagues are addressing this with an investigation into the beneficial effects of polysaccharides found in various species of aloe, comparing their ability to enhance immune defence and repair damaged skin.
“We know too little about the chemistry of these complex sugars,” says Rønsted. “They are very hard to analyse and we may yet find differences in the gel of different species.” The findings might even point to plants with greater powers than Aloe vera.
https://www.newscientist.com/articl...era-became-a-cure-all-and-cosmetic-superstar/
